Oklahoma flood control dams prevented $320 million in damages during 2007 storms.

USDA is an equal opportunity provider and employer.
This publication is issued by the Oklahoma Conservation Commission, in cooperation with the USDA Natural
Resources Conservation Service, as authorized by Mike Thralls, executive director. Copies have not been
printed but are available through the agency website, http://conservation.ok.gov.
October 2011
Major Storms Occurred in Oklahoma in the
Spring and Summer of 2007
Oklahoma had an unusual high amount of rainfall in
2007. Will Rogers World Airport in Oklahoma City had
recorded 56.95 inches of rain by the end of December.
This broke the all-time annual rainfall record of 52.03
inches set in 1908. The normal average annual rainfall is
35 inches.
The high rainfall amounts in the state during the spring
and summer again proved the value of flood control
dams. These dams were constructed by local units of
government (usually conservation districts) with the
assistance of the Oklahoma Conservation Commission
and the USDA Natural Resources Conservation Service
(NRCS) Watershed Program. There were 2,105 dams in
the state in 2007 (2,107 in 2011). The 2,107 dams
provide an estimated $81 million in average annual
benefits from reduced flooding.
However, just in the period from May to September 2007,
about 850 of the dams provided an estimated $320
million in benefits. It is estimated that another $48 million
in reduced flooding benefits would have been realized if
the remaining 300 planned dams had been constructed.
This is one of many examples of the benefits of the flood control projects across the state that are planned and
organized by local people with assistance from the Oklahoma Conservation Commission and the Natural
Resources Conservation Service Watershed Program. These projects address natural resource needs and
improve the quality of life for thousands of Oklahomans.
Remnants of Tropical Storm Erin reorganized over
Oklahoma resulting in heavy rainfall in the western
and central parts of the state.
An especially unusual event occurred in
Oklahoma in August 2007. Tropical storm Erin
came up from the Gulf of Mexico and
reorganized over Oklahoma becoming an even
stronger storm resembling an overland hurricane.
The storm stalled over the central and western
part of the state August 18-19th, delivering high
winds and producing up to 13 inches of rain in
some locations. Norman, Oklahoma, received
seven inches of rain in seven hours. The area
around the town of Geary, 50 miles west of
Oklahoma City, reported over 11 inches of rain
and over eight inches of rain fell in less than 12
hours in Caddo County.
Flood control dams prevented an estimated $30
million in damages during this two day storm.
"Although flooding occurred, damage would have
been much worse if not for the flood control
dams," said Mike Thralls, executive director of
the Oklahoma Conservation Commission.
"Sometimes the benefits of the dams go
unnoticed during storms, but a storm of this
magnitude really highlights how important the
dams are to the state," said Thralls.
Flood control dams impound water during heavy rainstorms and slowly release it through a pipe through the dam over a period of several days or weeks. This reduces the amount of rainwater that reaches a stream or river immediately after a storm and reduces flooding.
There are 129 watershed projects in Oklahoma that have been planned and implemented by local units of government (usually conservation districts) with assistance from the USDA Natural Resources Conservation Service and the Oklahoma Conservation Commission.
For additional information about watershed projects in the state visit the Oklahoma Conservation Commission website at: http://conservation.ok.gov or visit your local conservation district and NRCS office.

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USDA is an equal opportunity provider and employer.
This publication is issued by the Oklahoma Conservation Commission, in cooperation with the USDA Natural
Resources Conservation Service, as authorized by Mike Thralls, executive director. Copies have not been
printed but are available through the agency website, http://conservation.ok.gov.
October 2011
Major Storms Occurred in Oklahoma in the
Spring and Summer of 2007
Oklahoma had an unusual high amount of rainfall in
2007. Will Rogers World Airport in Oklahoma City had
recorded 56.95 inches of rain by the end of December.
This broke the all-time annual rainfall record of 52.03
inches set in 1908. The normal average annual rainfall is
35 inches.
The high rainfall amounts in the state during the spring
and summer again proved the value of flood control
dams. These dams were constructed by local units of
government (usually conservation districts) with the
assistance of the Oklahoma Conservation Commission
and the USDA Natural Resources Conservation Service
(NRCS) Watershed Program. There were 2,105 dams in
the state in 2007 (2,107 in 2011). The 2,107 dams
provide an estimated $81 million in average annual
benefits from reduced flooding.
However, just in the period from May to September 2007,
about 850 of the dams provided an estimated $320
million in benefits. It is estimated that another $48 million
in reduced flooding benefits would have been realized if
the remaining 300 planned dams had been constructed.
This is one of many examples of the benefits of the flood control projects across the state that are planned and
organized by local people with assistance from the Oklahoma Conservation Commission and the Natural
Resources Conservation Service Watershed Program. These projects address natural resource needs and
improve the quality of life for thousands of Oklahomans.
Remnants of Tropical Storm Erin reorganized over
Oklahoma resulting in heavy rainfall in the western
and central parts of the state.
An especially unusual event occurred in
Oklahoma in August 2007. Tropical storm Erin
came up from the Gulf of Mexico and
reorganized over Oklahoma becoming an even
stronger storm resembling an overland hurricane.
The storm stalled over the central and western
part of the state August 18-19th, delivering high
winds and producing up to 13 inches of rain in
some locations. Norman, Oklahoma, received
seven inches of rain in seven hours. The area
around the town of Geary, 50 miles west of
Oklahoma City, reported over 11 inches of rain
and over eight inches of rain fell in less than 12
hours in Caddo County.
Flood control dams prevented an estimated $30
million in damages during this two day storm.
"Although flooding occurred, damage would have
been much worse if not for the flood control
dams," said Mike Thralls, executive director of
the Oklahoma Conservation Commission.
"Sometimes the benefits of the dams go
unnoticed during storms, but a storm of this
magnitude really highlights how important the
dams are to the state," said Thralls.
Flood control dams impound water during heavy rainstorms and slowly release it through a pipe through the dam over a period of several days or weeks. This reduces the amount of rainwater that reaches a stream or river immediately after a storm and reduces flooding.
There are 129 watershed projects in Oklahoma that have been planned and implemented by local units of government (usually conservation districts) with assistance from the USDA Natural Resources Conservation Service and the Oklahoma Conservation Commission.
For additional information about watershed projects in the state visit the Oklahoma Conservation Commission website at: http://conservation.ok.gov or visit your local conservation district and NRCS office.